Ruling on Einstein's BH's:

Effort to image black hole, a chance to rule on Einstein
November 4, 2016 by Colleen Walsh

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Astronomer and Radcliffe fellow Dimitrios Psaltis is working on black holes as part of the massive Event Horizon Telescope project that will point a number of Earth's telescopes at the Milky Way's black hole this spring. Credit: Jon Chase/Harvard Staff Photographer
Being an astrophysicist and father of two is no easy task. Just a

extract:

Prioritizing his time is second nature for Psaltis, a lead scientist on the Event Horizon Telescope (EHT) project, a multinational effort involving more than 100 researchers, including his wife, former Radcliffe fellow Feryal Özel, and a series of super-powered radio telescopes scattered around the globe. Next spring those telescopes will turn the Earth into one giant eye when they all point to Sagittarius A*—the black hole at the center of the galaxy first forecast by Albert Einstein and his theory of general relativity, and since then the subject of study by countless theoretical physicists, among them the famous cosmic detective Stephen Hawking.

During his fellowship, Psaltis will refine the computer simulations he and his team will use when analyzing EHT data to determine the black hole's size and shape. Their results could prove that Einstein's theory—the notion that gravity is due to the curvature of the continuum known as space-time—is exact. Or, perhaps, just a little bit off.

"What we are looking for is not a description of gravity," he said, "but the description that happens to be the one that describes our universe."

To make those calculations, researchers will need to see what has thus far been invisible. But how exactly do you capture the image of a spinning, giant black abyss? You don't, said Psaltis. You take a picture of its shadow.



Read more at: http://phys.org/news/2016-11-effort-image-black-hole-chance.html#jCp

 

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It will be interesting to see what they come up with.
Thinking about it just now you should see a disk of light around the shadow made up of all the light behind which will be gravitationally lensed.
And given the available light (half a galaxy) it should be observable.

Although the dust may hide that light from us.

Just an unsupported thought.

Thanks for posting Paddoboy I find the project most interesting.

Alex

 

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Typical sloppy journalistic license. Einstein to his dying day refused to believe BH's were possible, and he certainly had no idea any such entity might be lurking at Sagittarius A*.

More nonsense. Of course they are looking to confirm or falsify GR which is a classical theory of gravity. And has nothing to say about what governs the vast majority of interactions in the universe - quantum physics.

 

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There is certainly a little irony there.
I had forgotten that little inconvenient fact.

When GR was presented the Universe was only the size of the Milky Way so I do find it curious that GR was so happily applied to the rotation curves of galaxies and delivered dark matter.

Alex

 

Science journalism going insane.

No observation is in principle able to tell if a general theory like GR is exact. All it can say - and will say, if my ether theory of gravity is a good approximation - is that GR is a good approximation.

Then, GR is not "the notion that gravity is due to the curvature of the continuum known as space-time". This notion is a property of the spacetime interpretation of GR. GR is not identical with one of its interpretations. And the spacetime interpretation in itself is not restricted to GR, but can be applied to a lot of other metric theories of gravity too.

But all the observation can support is GR. It remains neutral about the interpretation. My ether interpretation feels comfortable with the results of the observation too.

 

Hmmm.....

The disk of our galaxy , the stars , is on the equatorial plane of the globular center , hence lower gravity pull .

Hence the globular poles is where gravity is greatest . yet there are no stars drawn to the poles of our globular center .

 

How do you get the shadow of a BH?! And where do you get it?

Was there ever a negative experiment for GR? A test whose outcome we predicted in advance based on GR and observation was different?

I remember an observation around saggitarius BH and some cloud approaching it. We predicted that cloud will be mercilessly demolished but no it had a smooth nice walk, nothing happened as predicted. Can we say that GR was falsified?

 

What happened to that cloud?
I had forgotten about it.

What are your thoughts about a black hole causing a bright disk from all the gravitationally lensed light.
Sure light won't get past or around the event horizon but light passing further out will be lensed and given the light passing from the other side towards us it is difficult to imagine that such a disk will not result... And GR should support that idea.
A ring or disk should be visible and its diameter should relate to the size of the black hole.
Alex

 

Einstein ring ...

There we go I am inventing the invented.

Any black hole must cause a Einstein ring given the number of galaxies behind it...think of the Hubble wide field.

Wouldn't our sag a bend the light from the other half of our galaxy to form such a ring?

Alex

 

Pl search about G2 cloud, you will get the required info.

Swarzschild BH is conceptualized as point mass. You talk of gravitational lensing. If you a very strong point deflector and you have isotropic universe with light approaching almost uniformly from all direction, then ideally you should get a ring of lensed light irrespective of your observation point.

 

Oops, I wrote the same thing, typing when you posted. Since we do not get such rings, something wrong.

 

Such rings will still be difficult to observe but I think they must be there.
So say in the case of the ligo BH merger maybe we could search the approx region in an appropriate wave length which takes into account the red shift.

I don't know maybe they have already figured out to search for what I suggest.

Alex

 

Why it will be difficult?
Any point mass will have rings of background light irrespective of observer. Since background light is almost uniform in all direction, a BH should invariably look like a ring, as observed from anywhere.

 

While sloppy journalism maybe evident, GR does predict BH's.
And of course, we all at times sensationalise, even yourself qu-reeus in your past two threads, one with the headline/title of
"A simple proof Einstein got it wrong with GR"
Sorry, at this time I'm too lazy to find your other example, or it is probably lost in oblivion somewhere.

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Desperate times Schmelzer? Or do you just feel like some fun?

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While GR is certainly not "exact", it is the current overwhelmingly supported and correct theory of gravity, within its known bounds of applicability.
Your ether myth, as far as I know, remains a myth.

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Still, I understand where you are coming from: Any chance to resurrect it temporally is always worthwhile in your mind.
Let me add here, in my opinion, an exact theory is probably impossible and unattainable.
Even a potential QGT may not cover all contingencies, so to claim that GR is not "exact" is simply as I have told you before, to give some credibility to your ether myth.

 

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Obfuscation again? Not learnt anything yet?
You also once questioned the aspect of gravity in a BH, overcoming all forces, including the strong nuclear force, and even more bizzare, questioned the aspect of compulsory collapse once the Schwarzchild radius of any mass is reached.
Just put on your thinking cap, and it should be obvious to you what they mean by the BH shadow.....not hard at all, if you are open to scientific knowledge, rather then dictated to by some mythical baggage.

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They were wrong in their predictions, simple as that.
And there could have been many reasons, but none that invalidated the concept [as has now been verified] of BH's.
http://www.skyandtelescope.com/astronomy-news/g2-survives-black-hole-pass-10162014/

 

Not at all. Two publications accepted by Foundations of Physics. Nothing important, above directed against "refutations" or so of Bell's theorem, which have somehow survived peer review and been published. But in one of the papers, I have succeeded, as a sort of side remark, polemics against the accepted use of "local" instead of the correct "Einstein-local":
Schmelzer, I.: About a "nonlocal" local model considered by L. Vervoort, and the necessity to distinguish locality from Einstein locality, acc. by Foundations of Physics, arXiv:1610.03057

If you cannot distinguish a published physical theory from a myth, why should I care?

It is not clear, in principle an exact theory may be attainable. One can never prove that it is exact.

But, whatever, once you think an exact theory is unattainable, why do you post nonsense which should be obvious nonsense even for you? It is your text which contained the claim

So, my post rejects the nonsense you have posted. That I use them in my own interests by mentioning my ether theory in this context is something you have to live with, once you do not pay me for not doing such things. That you have given me a nice point is something you have to blame yourself.

 

As explained to you before, many papers are accepted even though purely hypothetical and speculatory, and a good percentage wallows in oblivion as apparently is your ether myth.

Any Mother will always see her own child as the most beautiful, no matter what.

Poor journalism is always on the cards. One could find much similar nonsense in your political rantings.
As of this date, GR is correct within its zone of applicability.

Reject all you like: No skin off my nose, but the gist of the article remains factual.
And of course you can use whatever you like in whatever manner you like, but with some of the "god driven"nonsense by others, and our exchanges in the past, I find your reactions as unprofessional.
But then again, you don't care!

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If you think so, show it. Quote the nonsense and argue why it is nonsense.

As Flat Earth Theory?

Given that you provide only an opinion, no argumentation, I see no reason why I should care.

As I have explained, I have this year rejected two "refutations" of Bell's theorem, which have been published. And, up to now, could have claimed about their papers that "its published, and nobody has published a refutation". Now they can no longer do this. This is how professional handling of nonsense written by others looks like.

 

No-one says otherwise.

Sensational? Whatever. If you wish to re-enter there and actually attempt to offer a technically useful and valid rebuttal, be my guest.

Please continue to be lazy - that way, just by default, you will not continue to derail this thread with deliberate side-issues.